Repeater switching telephone system



C. E. LOMAX REPEATER SWITCHING TELEPHONE SYSTEM Aug. 29, 1950 3 Sheets-Sheet 2 Filed Feb. 27, 1948 INVENTOR. Clarence E. Lomux v. u" A i atented Aug.

REPEATER SWITCHING TELEPHONE SYSTEM Clarence E. Lornax, Chicago, 111., assignor to Antomatic Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application February 27, 1948, Serial No. 11,435

The present invention relates to automatic telephone systems, and more particularly, to such systems incorporating repeater switching arrangements.

It is a general object of the present invention to provide in an automatic telephone system an improved repeater switching arrangement in which calls either from a calling operator switchboard or from a calling telephone station may be routed via switching apparatus and a common channel through a repeater to a called operator position, wherein the supervision from the repeater back over the calling route incident to answering of the call at the called operator position is selectively set by the switching apparatus in'accordance with the origin of the call.

Another object of the invention is to provide in a repeater switching arrangement of the character'noted, an improved arrangement for selectively controlling from the switching apparatus a supervisoryrelay provided in the repeater so that answer supervision is appropriately set in the repeater in accordance with the origin of the call.

A further object of the invention is to provide in an automatic telephone system an improved automatic switch and an improved repeater accessible thereto, wherein reverse battery super- 5 Claims. (Cl. 179-27) vision from the repeater over the switch is selecparticular arrangement of the circuit elements of the system, wherein the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, i which Figures 1 to 3, inclusive, taken together, illustrate the details of an automatic telephone system having incorporated therein the features of the present invention. Specifically, Figs. 1 to 3, inclusive, should be arranged from left to right in the order named and in end-to-end relation. I v

Referring now more particularly to the drawings, there is illustrated an automatic telephone system comprising an ofiice I0, an exchange 20 and an ofiice 30. The office [0 may be of any suitable type including an operator switchboard IN; the office 30 may be of any suitable type including an operator switchboard 3M; and the exchange 20 is of the automatic type serving a number of subscriber substations, not shown, and a number of paystations T303 and T306; The paystations T303 and T306, etc., may be of any conventional type such, for example, as that disclosed in U. S. Patent No. 2,137,407, granted on November 22, 1938, to Talbot G. Martin and Clarence E. Lornax. The exchange 20 occupies a tandem position with respect to the offices l0 and 33 and may constitute a community automatic exchange or C. A. X. The oflice I0 and the exchange 20 are interconnected by a group of trunk lines, including the trunk line I05; and the office 30 and the exchange 20 are interconnected by a group of trunk lines, including the trunk line 305.

The opposite ends of the trunk lines I05, etc., terminate in repeaters respectively disposed in the ofiice l0 and in the exchange 20, the trunk line terminating in the repeater I02 disposed in the office l0 and in the repeater H0 disposed in the exchange 20. Similarly, the opposite ends of the trunk lines 305, etc., terminate .in repeaters respectively disposed in the oiiice 30 and in the exchange 20, the trunk line 305 terminating in the repeater 302 disposed in the ofiice 3%] and in the repeater 3H) disposed in the exchange 20,. The switchboard l0! may be of any suitable manual dial type and has access to the repeaters I02, etc., each of which is of any suitable type. Likewise, the switchboard 3! may be of any suitable manual dial type and has access to the repeaters 302, etc., each of which is of any suitable type.

Also the exchange 20 comprises groups of connectors, one of the group including the connector 335 having access to the group of telephone lines, including the telephone lines 304 and 301 respectively extending to the paystations T303 and T306; the connectors 335', etc., being of the Strowger type. The telephone lines 304, 301, etc., are provided with line switches LS305, LS308, etc., individual thereto; and likewise, the subscriber substations are provided with subscriber lines also terminating in similar line switches, all not shown. The repeaters I I0, 3l0, etc., are respectively provided with incoming trunks 200, 300, etc., and outgoing trunks H0, 326, etc.; the' outgoing trunks I10, 326, etc., respectively terminating in line switches LS321, LS325, etc. The line switches LS305, LS308, LS321, LS32'5, etc. are of any suitable types. Also the exchange 20 comprises a group of selectors, including the selector S300. The selectors S300, etc., are accessible to the line switches LS325, LS305, LS308, LS321, etc., and have access to the incoming trunks 200, 300, etc.,

I tiple path for applying ground potential to the control conductor C323 of the trunk 320, thereby to complete an alternate holding circuit forenergizing the upper winding of the transfer relay R340 and to retain the line switch LS321 in its operated position. Moreover, this application of ground potential to the control conductor C323 of the trunk 320 marks the trunk 320 and consequently the selector S300 as busy to the other line switches LS325, etc., having access thereto.

The operator at the calling switchboard IOI then proceeds to dial the single digit comprising the directory number of the called switchboard 30I; whereby the repeater I02 repeats the impulses thereof over the trunk I05 to the line relay RI20 in the repeater I I0 causing the latter relay to follow. The first time the line relay RI20 restores, it completes, at the contacts I23, a circuit, including the contacts I32 and I48, for operating the dial relay RI50. Upon operating the dial relay RI50 completes, at the contacts I52, a path, including the resistors I38 and I31, the contacts I45 and the windings I29 of the repeating coil 125, for short-circuiting the upper winding of the answer relay RI60, thereby positively to prevent operation of the latter relay during dialing and to improve the impedance characteristic of the loop circuit extending over the outgoing trunk I to the line relay R350 in the selector S300. Each time the line relay RI restores and then reoperates, it interrupts and then recompletes, at the contacts I22, the circuit for energizing the windingof the hold relay RI 30; whereby the latter relay remains in its operated position during impulsing as it is of the slow-torelease type. Also each time the line relay RI 20 operates and then restores, it interrupts and then recompletes, at the contacts I23, the circuit for energizing the winding of the dial relay RI50; whereby the latter relay remains in its operated position during impulsing, as it is of the slow-to-release type. Finally, each time the line relay RI20 restores and then reoperates, it interrupts and then recompletes, at the contacts I2I, the loop circuit extending over the outgoing trunk I10 to the line relay R350 in the selector S300; whereby the impulses of the present digit are repeated to the line relay R350 in the selector S300 causing the latter relay to follow.

.Each time the line relay R350 restores and then reoperates, it interrupts and th n recompletes, at the contacts I, the circuit for energizing the winding of the hold relay R345; whereby the latter relay is retained operated during impulsing as it is of the slow-to-release type. Also each time the line relay R350 restores and then reoperates, it completes and then interrupts, at the contacts 352, a circuit, including the contacts 369, 349 and 344, for operating the vertical magnet M315 and for energizing the lower winding of the transfer relay R340; whereby the vertical magnet M315 is operated and restored repeatedly in order to drive the wiper carriage of the Strowger mechanism step by step in the vertical direction away from its normal vertical position and the transfer relay R340 is retained in its operated position as it. is of the slow-to-release type. When the wiper carriage of the, fitrowger.

mechanism is drivenon step in the vertical direction away from itsnormal vertical position the sets of switch springs S38I, S382 and S383.

are operated, More particularly, the set. of switch springs S383 isoperatecl in order to interrupt the holding. circuit for energizing the upper.

winding of the transfer relay R340; howeventhe latter relay is retained in its operated position during impulsing as it is of the slow-to-release type and the circuit for energizing the lower winding thereof is completed intermittently. At'

the conclusion of the. present digit, the wiper carriage of .the'Strowger mechanism occupies a position adjacent to the level in the associated. contact bank terminating the group of incoming trunks, including the incoming trunk 300 ex tending to the repeater 3I0, and the set of switch springs S384 is operated. More particularly, the

set of switch springs S384 is operated in order to disconnect, at the contacts 385 thereof, the EC wiper 314 of the Strowger mechanism from the.

control wiper 313 thereof; and to prepare, at the. contacts 385 thereof, a connection between the EC wiper 314 of the Strowger mechanism and the EC conductor C324 of the trunk 320. at the conclusion of the present digit, the line relay RI20 in the repeater H0 is retained in its operated position in order to interrupt, at the contacts I23, th circuit for energizing the winding of the dial relay RISE; whereby the latter relay restores shortly thereafter, it being of the slow-to-release type. Upon restoring the dial relay RI interrupts, at the contacts I52, the path for short-circuiting the upper winding of the answer relay RIBB; whereby the upper winding of the answer relay RI is again insertedin the loop circuit extending via the line conductors CI1I and CI12 of the outgoing trunk I 10 to the line relay R350 in the selector S300. Accordingly, the line relay R350 is retained in its operated position interrupting, at the contacts 352, the circuit for energizing the lower winding of the transfer relay R340; whereby the latter relay restores shortly thereafter, it being of the slow-to-releas type.

Upon restoring the transfer relay R340 interrupts, at the contacts 341, the path for applying ground potential by way of the winding 33'! of the dial tone transformer and the lower winding of the line relay R350 to the line conductor C322 of the trunk 320; and completes, at the contacts 342, an alternative path for applying ground potential by way of the lower winding of the line relay R350 to the line conductor 0322. Accordingly, at this time the return of dial tone current over the connection to the calling switchboard IOI is interrupted. Also upon restoring the transfer relay R340 completes, at the contacts 343, a circuit, including the contacts 348, 355, 308 and 311 and the set of switch springs S33I, for operating the rotary magnet M313. Upon operating the rotary magnet M316 drives the wiper carriage of the Strowger mechanism one step in the rotary direction away from its normal rotary position; and interrupts, at the contacts 311, the operating circuit therefor. Accordingly, the wipers 311, etc., of the Strowger mechanism select the first contact set in the previously selected level in the associated contact bank terminating the first incoming trunk in the group including the incoming trunk 3&3 whereby the idle or busy condition of the first incoming trunk mentioned is tested by the test relay R355. More particularly, at this time ground potential is applied by way of the contacts 341 and the winding of the testirelay R355 to the control 7 Also theawindingrofiftheetest relay R355 ie-sl'ror-t v cuitediby theeapplication of ground' potential the test rel-ay fifie interruptsaat the contacts 35 'REEE Also theswitcbtlironghi.relay:

tendingt'o the reoeat'er 3131 Accordingly; at=th time an alternative loop circuit eicompl et'ed-wew tween the. ueneri winding. crate-e answer relay R5513 in: the repeater-r7! iili'anclrthe line I'Glfl Yfil'lp the repeater are. Atthieti-methe repeater Sit; operates. to returrr ground potential-es e thereaten;

V wiperrflzof the Strowgenamechanism;whereby? upon the iCOHtLOI'iCOHIillCtOI of ith'e firstincoming-f:

trunknmenti'onedi in: the event this" incomingtrunk; iszbusyatthis time; On the other: hand: initheaeventithe first in'comingitr unk mentioned! isz idle at. this time; batteryi potential appears uponuthercontrol: conductor thereof .1. and is ap piiedcto-sthe;control rwiper 3T3Tof: the Strowger.

mechanism;. thereby completingr a circuit" for emergizingzzthe windingerof theitest re1ay R3i55 "-caus=-- ing the latteri relayz-to 0136111128: Eir'st iassum'ine thatrthezfirst' incomingatrunk?mentioned is 'bhsy thec-windingsofthe test relay-R355 is: short cir cuited'; whereby the vrotary. magnet' M3'i t upon restoringxreoompletes, at the contacts 311; the-- operating r circuit therefor; Aecorriingly; the. roa. tarry; magnet 1 M3 7 fizoperates buzzer" fashionuntil ancidlerz-incoming trunkicirt'rthe groupsmentioned is: selected effecting"- operation-of: the" test '.re1ay R3'55i';

N 0W1 assuming; that: all: of the: incoming Ptrunkso precedingztherincomingittrunkii3% extending to theirepeater:3til arefbusy at this.='time, the rotarymagnet zMil'ifi ioperatesa buzzer. fashion to drive" the: wipern'carriage' of the Strowger: mechanism step by stepinwthe rotary direction until the wiper setxselectsztlie incoming trunk Stile At this-time battery potential appearing upon tilt-2* control:- conductor C393 of the incoming trunk 398 completes ithe previously traced circuit for-' operatin the test relay R355 Upon operating the circuitfor operating the rotarymagnetmgl thereby positively to prevent i fiirtr'fer operation thereof and: consequently to arrestthe trunle" hunting operation above described: Also the and a pat including the contacts 312% and. 3137; for s-licrt 'circuiting the winding of the tee ter-rupts at -the contacts 36 i" and 54% the norm connections between the upper "'ancltlowerwind ings'-' of the line relay; and the linev con-- cln'ctore- C32'l 'andCS'ZZ" of" the trunk; 329; and." completes, atthe contacts '3fi2i'and 35'3"connec.. tions betweenth'e lihecondiictors .C32Land 13.32% and th line wipers 3'! Panel 2372 ofithe Strowger. mechanism: and consequently the line cond'uctora. C36? andCBEZ of the incomingrtiaunkififiifier 3&5; and consequently to athe control: wiper 3? I 0 n'itheistrowgen mechanism-th owerto complete: lternative; helding circuitg including-the" con afifilandl-fii i forfenergizingaithei minrlingro thetswitch-throughrrelayzfifieiizandaanralternativeit applxingiigrwndenotentialfito the-coon; 2;

tron conductor @3233 of the trunk: 326 in =ordi to retain therlme switch LS32 T in' its operated positiona Also--at'i-thi's ti'm the repeater 31H ope-rates to return rihg bac -tone current overthe ime conductor C30 1 of" the incoming trunk Silii and consequentlyover the" connection to thecallingswitchboard I 04 in order to Y indicate tliat the called; switchboard fiii is being-signaled aiitliis tim'e; Finally; the repeater -3'i ll operates'-- to -transmiii a call? signal =over'the trunk 305 *to" tffe' 'repeater fim'? whereby the repeater tflz -r' peats the-=-call signa'l to the-= cal-led? switchboard-" ind' 'r'cating to the operator thereat that a- Waiting-- tobe= answered on-'-'the" repeater" thus short oircuited thelatter" relayrestoree shortly thereafter 'Without effect at this time.

A-ie'o When t e circuit i for energizing in series the-upper and lower-windings of the line relay R359 is thus interruptdf the line -relay*rcstorcs-- Without effectat this time: 1 Further upon-open ating 'the-switch-throughrelay R355" interruptei; at the contacts fificthe-circuit-for retaining operated the h'old relay Riifi in' order to cause' thelattenrelayto restore shortly thereafter; it boing of th'e=s1ow-to-re1ease type: Upon restor ing the hold relay RSAS -interrUptS, at the con tacts the or-iginaP-holding circuit for en'er ugiz'in'ga the winding ofthe switch-through"-relay tai-i lecl iir their" operated" positions fromground potentialappliedin the repeater" 3 HI-to" the eon trol' conduot'or C333 oi th'e incoming trunkBil-i9? Flhaily th'e switch through relay R366 completes;v at tl i'e contacts 3'85; 'a-connectiongincluding' the":

.'-co'ntacts*: 389' of the set of switch springs? 38:2";

beinweernthe EG' cond-fictor (i 'gd ofthe trunkiiii'fi and the wiper 374 of" the Strowger mechaanisnr; however; Without "effect at this'tirne since the lineSwitcH 3'21 'oloesnot comprise an'EUwiperi.

Accordingly, in thepresentexample no potential is"=l'applied via the path-including: the EC 'wiperfif BEF l-i of tHe" Strcwgermechanism to thet'E'C' con dtictQWCflMbf-the incoming trunk SEiFext'ending; w ther-repeater 31 0. l 1

After the operator at the called; switchboard 3Bl' receii/e'sthe call signalindicating thepresk once of a call Waiting to "beanswered' uponthe' repeater 30%? she" connectstheretocausing the" repeater- 302 to control" the repeater- 31 0 f; where:

I by the repeater 3 l-B=operates 't'o reverse th'e polam ity of the loop-circuit?including the-line con ductors 039 and 0-382 "of I the incoming trnn'k 356; whereby "the-upper 'W-incling'ofthe answer relay Rl'l iififin the repeater l l 0" is poled to oper ate. Also therepeater'3-i(l 'interrupts the return of ring-back tone current over theline conductor" 03!! I of the incoming trunk'30fl andconsequentlyfi this signal over'themonnection in order to' indicate to the operator at the calling switchboard IBFthat'the-operatOr at the called switchb'oardt' 3 I3 I has answered the present call. Upon operating theanswer relay R1 60 the repeater lrl'lli completes; at the contacts jl 6i a circuitfor'operating=the==supervisory relay R1351" Upon operat ing the supervisory: relayR'l 3?:revrses; at "the contact's--- I35, Y I31, l38and I39," the polarity of."

the loop circuitextendin'gv. between the. repeater lllli'and the-upper aridlbwer windings of. the. 11ne rel9iyRJl23-f whereby the repeater I Uzi-open atce to return ananswer signal "to the calling the line switch LS321.

switchboard' I M thereby to indicate the circumstance noted. At this time an established connection is completed for two-way communication between the calling switchboard IOI and the called switchboard 30I At the conclusion of the established connection, when the operator at the called switchboard 30I disconnects, the repeater 302 is controlled in order to govern the repeater 3I0; whereby the polarity of the loop circuit, including the line conductors C30I and 0302 of the incoming trunk 300 and the upper winding of the answer relay RI60 in the repeater H0, is reversed; whereby the answer relay RI 60 is poled to restore. Upon restoring the answer relay RIB!) interrupts, at the contacts I6I, the circuit for retaining operated the supervisory relay Rl35. Upon restoring the supervisory relay RI35 restores, at the contacts I36, I31, I38 and I30, the polarity of the loop circuit extending between the repeater I02 and the upper and lower windings of the line relay RI20; whereby the repeater I02 operates to return a disconnect signal to the calling switchboard IOI. The operator at the calling switchboard IOI then disconnects from the repeater I02; whereby the repeater I02 interrupts the loop circuit extending therefrom to the upper and lower windings of the line relay RI20 causing the latter relay to restore. Upon restoring the line relay Rl20 interrupts, at the contacts I22, the circuit for retaining operated the hold relay RI30; whereby the latter relay restores shortly thereafter, it being of the slow-to-release type. Upon restoring the hold relay RI 30 interrupts, at the contacts I 3|, the circuit for retaining operated the switch relay RI40. Also upon restoring the line relay RI20 interrupts, at the contacts I2 I, the loop circuit including the line conductors GUI and CI12 of the outgoing trunk I10 extending to the repeater 3I0, thereby to effect the subsequent release of the repeater 3I0. Also the last mentioned loop circuit includes the upper winding of the answer relay RI60; whereby the winding mentioned is deenergized. Upon restoring the switch relay RI40 interrupts, at

the contacts I 45, the circuit for energizing the lower winding of the answer relay R I 60; however, without effect at this time since the answer relay RI60 already occupies its restored position. Further the hold relay RI30 interrupts, at the contacts I33, the path for applying ground potential to the control conductor C203 of the incoming trunk 200; and recompletes, at the contacts I3s,

the path for applying battery potential by way of the resistor I49 to the control conductor C203. Accordingly, at this time the incoming trunk 200 and consequently the repeater H0 is again marked as idle to the selector switches S300, etc., having access thereto.

When the repeater 3! is released, ground potential therein is removed from the control conductor C303 oi the incoming trunk 300 and consequently from the control wiper 313 of the Strowger mechanism in the selector S300 interrupting the holding circuit for retaining operated the switch-through relay R360. Also ground potential is removed from the control conductor C323 of the trunk 320 in order to effect the release of Upon restoring the switch-through relay R330 again completes, at the contacts 30! and 364, the normal connections between the upper and lower windings of the line relay R350 and the line conductors C32I and C322 of the trunk 320. Further, the switch-through relay R360 completes, at the contacts 369, a cira cuit, including the contacts 352, 345, and 342' and the set of switch springs S382, for operating the release magnet M318; whereby the Wiper carriage of the Strowger mechanism is released and returned to its normal rotary and vertical positions. When the wiper carriage of the Strowger mechanism is thus released, the sets of switch springs S38I, S382 and S303 and S330 are operated. More particularly, the set of switch springs S382 is operated to interrupt the circuit for operating the release magnet M310; the set of switch springs S384 is operated in order to close the contacts 385 thereof, again connecting the control wiper 313 and the EC wiper 314 or" the Strowger mechanism; and the set of switch springs S383 is operated in order again to apply battery potential via the upper winding of the transfer relay R340 to the control conductor 0323 of the trunk 320. Accordingly, at this time the trunk 320 and consequently the selector S300 is marked as idle to the various line switches LS325, etc., having access thereto. At this time the established connection between the calling switchboard IElI and the called switch board 30I is released and all of the apparatus involved therein is completely released and available for further use. I

The extension of a call from the calling switchboard 30! in the office 30 to the called switchboard I 0| in the office I 0 is the same as the extension of such a call in the opposite direction as described above. Specifically, the operator at the calling switchboard 30! connects to an idle repeater, such for example, as the repeater 302; whereby the repeater 302 seizes the repeater 310 over the trunk 305. The repeater 3I0 operates to seize the line switch LS325 over the outgoing trunk 326 and to mark the incoming trunk 300 as busy to the selectors S300, etc, having access thereto. The line switch LS325 operates to seize an idle selector S300, etc. Assuming that the line switch LS325 selects'the trunk 320 extending to the particular selector S300, dial tone in the selector S300 is returned over the connection and the operator at the switchboard 300 proceeds to dial the single digit comprising the directory number of the called switchboard IOI. Initially, a loop circuit is completed between the repeater 3H! and the upper and lower windings of the line relay R350 in the selector S300; whereby the latter relay follows the impulses of the present digit bringing about operation of the selector S300 in the manner previously explained. In the present example, the Strowger mechanism first selects the group of incoming trunks, including the incoming trunk 200 extending to the repeater H0, and then an idle incoming trunk in this group. For example, the selector S300 may select the particular incoming trunk 200, the trunk 200 being marked as idle by the application of battery potential via the resistor I43 and the previously traced path to the control conductor C203 thereof. When the Strowger mechanism selects the incoming trunk 200, the test relay R355 and then the switch-through relay R360 are operated;

whereby the line relay R350, the test relay R355 and the hold relay R345 are restored; all in the manner previously explained. More particularly, the switch-through relay R350 completes, at the contacts 332 and 333, a loop circuit, also including the line wipers 31! and 312 of the Strowger mechanism, the line conductors C20! and 0202 of the incoming trunk 200; the contacts 212 and 214, the d s I20 and I28 of the repeating coil I25, and the contacts I42 and I40 for energizing in se i s t e upper and lower windings of the line relay R2! 0, in the repeater l-lrll via; the line con-- ductors'C3-2t andZCBZ-Z'. ofthe trunk. 3-20and the. connection back to the repeater 3-ii0;;;wherebytheline relay R2 l 6 operates.v

Upon operating the line relay R2 t: completes, at the contacts 2| l, a circuit. for operating the. hold: relay- R236; andcompletes, at the contacts 242, a circuit for operating. the supervisory relay Iii--35-- Upon operating the holdrelay R23B-GOIII- pletes, at the contacts233,a circuit for operating the control relay RZGE; and completes, at the contacts 231 apath. for: applying ground; potene tial= by way of. the, lower winding of the tone start relay R220 to the control conductor 6283 of the incoming trunk 2116;. The tone. start relay R2 25 then operates. to complete, at the contacts 229., a path for applying ground potential to the tone start conductor. C222 in order to.- insure the application. ofjring-back tone upon thering-back. tone conductor Ci2-4z Upon operating; the con.- trolzrelay R2451, completes, at the contactsZ-AZ; a path; including: the contacts: 34,. '15 and 27:2; for connecting the ring-back tone conductor C 124" to the line conductor C221: of the incoming trunk: 2.86.; whereby ring-back tonevcurrentis returned; over the connection in order to indicate to the operator at'the calling. switchboard 30'! that the called? switchboard HM is being signaled. Uponoperatingthe supervisory relay R Hi: reverses, at the contacts E38, I31; 138' and L39, the: polarityof the connection between th v upper and lower windings of the. line relay R120 and the line conductors Cite. and- C111!- of. the trunk I05; whereby: the repeater. M2: is governed oven the I 05 totra-nsmit a call signal to the called switchboard; Hi5 indicating that a: call is waiting: tor-beanswered uponv the repeater I102; The operator at the called switchboard- HH answers the call: by con-- necting to the repeater L92; wherebytherepeater till is controlled to complete a. loop circuit: for: energizing in. series the upper and: lower wind-- ingsof" the line relay Ri-Zilcausing the. latter relay to operate. Upon operating. the line relay Ri-29 completes, atlthe. contacts 122, the" circuit for operating: the hold relay 135E30 and. a, multiple circuit, also including. the contacts 24 iand. the. resistor 275,. for operating the supervisory; relay R223. At this'point it, is noted that 'the: supervisory relay R210- is operated since: groundv p0- tentialin the selector S308. is not applied to-the- E6. wiper 32M of the Strowger mechanism: and consequently to the' EC conductorCZM: of theincoming trunk 2% Upon operating the supervisory relayRZHi reverses, at the? contacts. 211:, 212, 213; and- 2M, th polarity of the loop circuit, including the. line conductors-C201? and (320.2 of thBrllElCQl'IlLl-Ilgtrunk 2011- extending between the line relay R241? and the repeaterfi-tQ-j Upon operating the hold relay Hi3!) interrupts, at the contacts: iii-l, the path for returning ring-baclc tone/current over the connection to the calling switchboard; 3 3i in: order to indicate! to: the operator thereat that the call: has been? answered at the called switchboard NH. A-lso the hold relay R'ifiiii' completes, at the contacts l=3i a circuit,

including the contacts 2M3- and. 266; for operating they answer relay RZEGH Upon operating the answer relay R255 completes, at the contacts 25 and 252, a path, including thecontacts 2?- and i-l-li qfor bridging'the upper winding of'the tone start'relay H226 across the lineconductors C201: and C292; whereby any tone'currenttraversing the lowerwind-ing of the tone start relay R225- vi-a'thecontrol' conductor: C293 of the incoming trunk 26a may induce a corresponding ton 11;

rent inthe; upper winding; oi the tone start. relay R228 causing this tone current to be supplied: via the repeating coil L25, the: trunkiiiii, and therepeater tea to: the called switchboard. [251; This arrangement permits identification of the class; oi a. calling; telephone station: or the like in. the exchange; 29." to theoperator' at the. called switchboard IM'; which circumstance is not-present in. this example.- andis consequently of, no present utility;

Aiso upon operating; the answer relay R-3= closes the contacts 253 and sets its armature; RA2-54 into: vibration; whereby the contacts 253: are closedintermittently energizing; the winding; or the-timer relay R266. Since the timer relay R269; is of theslow-to-operate type, operation thereof. is accordingly delayed. Upon operating thfitlillfil relay R260; completes-,at the contacts 2&5, a holding, circuit, including the contacts. 246 and Hil for energizing the winding thereof; completesat the contacts 26L adirect path for short-circuiting the lower winding of the tonestart' relay R220 and. a direct multiple path for applying ground potential to the; control con.-

; ductor C2i3- 0f the incoming trunk 290; and completes; at. the'contacts 2.63, a holding circuit, in

eluding the-contacts 2-32,, for retaining operated the: hold relay R230. Also the-timer-relay R252. interrupts, at the contacts 266, the circuit for retaining operated the answer relay R250; whereby the latter relay restores to interrupt, at the. contacts 254-, 2-52 the path. for connecting; the upper winding.- of. the tone start relay R229: across the line conductors C291: and. C202- oi the incoming trunk are in order: to out. ofi. the tone testing arrangement previously described;

When, the polarity: of theloop circuit including. the-line conductors (32M and: C2 92. of. the incom ing trunk Z-iiil is reversed between the upper and. lower whidings of the line. relay mic and the repeater. tllthe-repeater 3H1 is operated to-gov.- ern: thev repeater 3132 over the trunk 305 whereby the-repeater 3B2 returns an. answer. signal to the calling switchboard 30:! indicating the-circumfstance noted; At'this time an established con nection is completed for two-way communica:- tion betweem the calling switchboard 301 and the called. switchboard i l! I;

At the conclusion of. the established connection,, when: the operator at the called switchboard [-01 disconnects; the repeater N12: is con-- trolled. to interrupt the loop. circuit extending via. the trunk I05 to the upper and lower windings of. the: line relay Rl20. in order to cause the latter relay to restore. Uponrestoring the line relay-R interrupts, at the contacts I22, the circuit for retaining operated thehold relay R l-3l1;. whereby they latter. relay restores shortly thereafter, it being of the slow-to-release type. Also the line. relay RIiZUinterrupts, at the contacts I22, the multiple circuit for retaining operated the; supervisory relay R210; whereby the latter relay restores, at the contacts 2', 212, 213 and 2.14,. the polarity of, the loopcircuit, including the line conductors 020 I. and C202 of the incoming trunkv 2.813; between the upper and lower windings of the linerelay-RZ Ii! and the-repeater 3-! 9; whereby the repeater 3% controls the repeater 302 over thetrunk- 385: in order to cause the repeater 302 to transmit a disconnect signal to the calling switch-- board 39+ indicating the circumstance noted. Upon restoring the hold relay BB9 interrupts, at the contacts 131', the holding circuit for retainingoperated the timerrelay R260. Subsequently; whenthe operator at: the'calling. switchboard 3M then an idle connector therein.

13 disconnects the repeater 302 controls the repeater 3I0 over the trunk 305; whereby the repeater 3I0 interrupts the loop circuit extending via the incoming trunk 200 to the upper and lower windings of the line relay R2I0 causing the latter relay to restore. Upon restoring the line relay R2I0 interrupts, at the contacts 2I2, the circuit for retaining operated the supervisory relay RI 35. Upon restoring the supervisory relay RI35 restores, at the contacts I36, I31, I38 and I39, the polarity of the line conductors C I and CIO'I of the trunk I05 with respect to the upper and lower windings of the line relay RI20. Also the line relay R2I0 interrupts, at the contacts 2I I, the circuit for retaining operated the hold relay R230; whereby the latter relay restores shortly thereafter, it being of the slow-to-release type. Upon restoring the hold relay R230 interrupts, at the contacts 233, the circuit for retaining operated the control relay R240; and interrupts, at the contacts 23I, the path for applying ground potential by Way of the lower winding of the tone start relay R220 to the control conductor C203 of the incoming trunk 200 and consequently to the control wiper 313 of the Strowger mechanism and the control conductor C323 of the trunk 320. At this time the selector S300 and the line switch LS325 are released in the manner previously explained. Upon restoring the control relay R240 recompletes, at the contacts 244, the path for applying battery potential by way of the resistor I49 to the control conductor C203 of the incoming trunk 200 in order again to mark the incoming trunk 200 and consequently the repeater IIO as idle to the selectors S300,

etc., having access thereto. When the selector S300 is released, the set of switch springs S383 is operated in order again to apply battery potential by way of the upper winding of the transfer relay R340 to the control conductor C323 of the trunk 320 in order again to mark the trunk 320 and consequently the selector S300 as idle to the line switches LS325, etc., having access thereto. At this time, the established connection between the calling switchboard I and the called switchboard IOI is released, and all of the apparatus involved therein is completely released and available for further use.

In View of the foregoing it will be understood that a call from the calling switchboard IOI in the office I0 may be extended to a called subscriber substation or paystation in the exchange 20 in a manner similar to that described above. For example, a call from the calling switchboard IOI in the office I0 to the called paystation T303 in the exchange 20 may be first routed via the repeater I02, the trunk I05, the repeater IIO, the outgoing trunk I I0, the line switch LS32'I, and the trunk 320 to the selector S300. Thereupon the operator at the calling switchboard IOI dials the three digits comprising the directory number of the called paystation T303. The selector S300 follows the first digit selecting first the group of connectors, including the connector 335, and

ventional practice. Assuming that the paysta-' tion T 03 s idle at this time, the connector 335 For example,

connection between the calling switchboard I00 and the called paystation T303 and operates to reverse the polarity of the line conductors C33I and C332 of the trunk 330 and consequently the polarity of the loop circuit extending back to the upper winding of the answer relay RI' in the repeater IIO causing the latter relay to operate.

The answer relay RI60 effects the operation of the supervisory relay RI35 and the consequent reversal of polarity of the line conductors CI06 and CIOI of the trunk I05; whereby the repeater I02 is controlled to return an answer signal to the calling switchboard IOI in order to indicate to the operator thereat the circumstance noted. At this time an established connection is completed between the calling switchboard IOI and the called paystation T303.

At the conclusion of the established connection when the person at the called paystation T303 disconnects the connector 335 operates to restore the polarity of the line conductors C33I and C332 of the trunk 330 effecting the consequent restoration of the answer relay RIBO and the supervisory relay RI35 in the repeater H0. The supervisory relay RI35 restores the polarity of the line conductors C I 06 and C I 01 of the trunk I05 causing the repeater I02 to return a disconnect signal to the calling switchboard IOI in order to indicate to the operator thereat the circumstance noted. When the operator at the calling switchboard IOI then disconnects the repeater I02 is released effecting the release of the repeater H0 and the consequent release of the line switch LS32'I, the selector S300 and the connector 335 in a manner similar to that previously explained. When the connector 335 is thus released, the telephone line 304 extendingto the called paystation T303 is again marked as idle to the connectors 335, etc., having access thereto. At this time the established connection between the calling switchboard NH and the called paystation T303 is released and all of the apparatus involved therein is completely released and available for further use.

In view of the foregoing description, it will be readily understood that a call may be extended in a substantially identical manner from the calling switchboard 30I in the ofiice 30 to a called subscriber substation or paystation in the exchange 20.

Assuming now that a call is to be extended from a calling subscriber substation or paystation, such for example, as the calling paystation T303 in the exchange 20 to the called switchboard IOI in the oflice I0, the person at thepaystation T303 first initiates the call. The paystation T303 may be of the post-payment type; whereby the present call is immediately initiated without the deposit of a coin thereat. More particularly, the line switch LS305 is controlled over the telephone'line 304 extending to the paystation T303 and operates in order to select an idle trunk in the group, including the trunk 320. For example, the line switch LS305 may select the particular trunk 320 extending to the selector S300; whereby the selector S300 is seized, the line relay R350 therein operating over a loop circuit extending back to the calling paystation T303.

'trunk 200, and then an idle incoming. trunk :-.therein. For example, the -Strowgerumechanism -may=se1ect the particular incoming trunk200 ex- =tendingtothe repea-ter: l I whereby the testrelay.--R355and the-switch=through relay R360 in the-selector S300 operate. The switch-through relay R300 effects the subsequent restorationof the: test relay- R355 and the line relay- R350- and the hold relay'R305. Specifically, the line relay R2 [0 in the-repeater I is operated-over the loop -.-.circuit including the line 'conductors Cfll and- C202 of the incoming'trunk 200 and the line con- ..ductors C321 andCBZZ'of'the trunk-320-extending back to the ca-llingwaystation T303. Upon operating the line relayxR2i0-efiects the operationaof the hold'-relay-'R230 and the consequent .operation of the :control-relay R240. Alsothe linere1ay-R2|0 effects the operation of the super- -visory relay-Rl35;x=andthe hold relay R230-effectsfthe operation ofwthe tone start relay. R220. :At. this :timez-theset-of switch springs S384in the selector $300.:is again operated; whereby the EC wiper J14: oftheStrowger -mechanism is con- ;-nected via the "contacts 386 of the set-of switch springs-S384 andthe-contacts 365 to the EC conductor C324 :of thetrunkn320.

:.-Inthe 'presentaexample, ground -potentialin the line st etch-LS3iifiirindividualto the telephone line 30!; lexten ding to the call-ingspaystation T303 -.isapplied viathe -1-EC wiper thereof to the EC conductor:C32-0 of-thetrun-kv320 completing a path also i11cluding"the.-.EC conductor-C204 of "theincoming trunk 1200 fereapplying ground po- .tential to the adjacent terminal of the supervisor-y relay -.R2.l0 and efieetively removing the applicationpfbattery potential-throughtherev ,sistor @225 rf'romwhe: adjacent terminal of the supervisoryrela .3210; Fall ror purpose more fully: explained'hereinaf-ter. 'Also, :at-this time, -batterypotential having pays-cation tone superimposedthereonie-applied in-the line switch LS305 via the control wiperthereetto the control conductor-C323 eiathe'trunk $29 and con- :sequently extends-via the :ccntrol .wiper {51.3- of the .Strowger mechanism -and the control-con- @ductor C203 .of theincoming trunk-zllethrough thelower winding. of the toneastart re1ay-R220 inducing a corresponding paystation tone the -.upper -winding thereof eforea-z-pnrposeorn-ere; hilly explained hereinafter. Jlt- .th-is' time the operated wherehythe repeater tel-operates to transmit z'a scall signal to the switchboard l 0i indicatingto the eoperator thereat the cireumstance th'at acall is waiting-to be answered onrthe repeater-i 02.

Whenthe-.-.operator at :the :called: switchboard 0l=-ianswersethe call by connecting to the repeater 51102; theflinerelayeRfi-El inthel-repeaterei tflwiskopaerated 'reitectingeoperationwzofathe hoiderelaycfittfl wand-the conseqezentroperationlofirne answer: relay z-R250. Uponroperatin'g the; answer bridges the upperwindingaof fthectonenstartarelay :REZQ across :the 311I1e2fC6EiIIC tOIS "K323i eanil c6202 .=of ithe .incoming tron-k? 2 0.0 rand :thereafter effects operation =ofwthe timer; relay R200. The

timer relay R260 then effectsethez'restorationiof hithe answer relay :R'350 and 'rshortecircuitin'g 46f the lower wirrding of the tone: starts-relay 5.2 20. 'Upon restoring 'sthe answer *srela-y rR250 :z'discen- "nects the upper" winding of =theaetonesstartzrelay --R220 from across the :dine:conductorseGEiH aand (2202 of the incoming trunk 1:200. Duiiing --t:he short-time interval vthat the rapper winding ccif the ltone start relay Ra l .1 is bridged wacross ithe :line conductorstcim l and. C202of the aincornine trunk- 200 ithe jpaystati-on itone rduced-stherein fromthe lower"winding thereofi'isimpressed via itherrepeatingecoilr125 and the-tmnk -i05 upon the repeaterifiZ andec(msequently isr returned -ito --.the 'cal-ledeswttchboard-: t0! "indicating to. the;:op-

' erator thereatthat the; present callflhiginates at .tending: back to-Ithe ca-llingzzpaystation T303 prevents wnormal operation of apparatus disposed therein and the conseqnentxblockingofztlie transmitter of thetelephone-instrumental;thevcal'ling paystatien [Fl-303. :In'passingdt is; noted that? had thisapparatusr-rnentioned :openated- 'to block-op- :'-eration of I the; transmitterqof the telep honerin- =strument nat th calling paystationwfmfl, the

:.-blockrnentionedwcoul'd :have 'been" removed only .-.arrangement- .-per1nits *free calls :frem the "calling -paystation T3.03to the called :switchhoarddti.

At this time aneestahlishediconnection riS'JCQm- --zpleted.:.f-or two =wa-y. communication *between the cal-ling rpaystation-BQS-arrd the calledswitchboard At 1 the CCHCIUSiOIIa'Of .the established cennecation, when the -.-person +atcthe calling; paystation T303 disconnects "the sloop circuit extending via the line conductors CEBINand-GZEZ oftheincoming trunk 200 to the line relayzrRZi 0 the repeater I I0 is interrupted causing thez'latte relay to restore and effect the restoration#ofthesuper- =.ing:v.ia the trunk between :the-repeater-wl and the-line relay RIM-causing the repeater-.H 2

.. to return a disconnectrsig-nal to thecalled switchboard l0l"indicatingrto:.the operator theratthe :oircumstance noted. When :Ltheioperatorratethe called switchboard then disconnects from the. I

repeater l02,- the repeater I02 and the repeater H0 are released efiectingthe release of the marked as idle tolthe selector S300, etc rhaving access thereto; and when the line switch 15305;;

is thus released the telephone line 304 extending to the paystation T303 is again marked as idle to the-connectors 335, etc, having access thereto I At this time the established" connectionbetween thecalling paystation T303 and the called switchboard 10! is released and alLpi, the apparatus involved therein is completely released and available for further use. 1 1' vIn view'of the foregoing description it will be: understood that a call initiated at a paystation, v such for example, as the paystation T303 in the exchange 20hmay beextended in a substantially identical manner via the telephone line 304 the line ;switch LS305 ,;,the trunk ,320, the selector S300, the incoming trunk 300, the repeater 310, the trunk 305 andgthe repeater 302 to thecalled switchboard 30L in the oince 33. In this case the, person at the calling paystation T303 dials a single digit comprising the directory number of the called switchboard 30! after the line switch LS305- has seized the selector S300. Again the line switch LS305 the set of switch springs S384, the 'jEC wiper 314 of thestrowger mechanism and the EC conductor 0304 of the incoming trunk 30,0;are utilizedin order to prevent operation oi the; supervisory relay in the repeater 310 when;

the; call is answered at :the called switchboard 30],; Thus it will be understood that acall may be extended from the calling paystationT3ll3 to the called switchboard 30! without deposit ing a coin at the calling paystation T303; I V I Finally, considering the extension or a local call from a calling subscriber subscription or paystationto a called subscriber substationior paystation'in the exchange 20, and by way of ex: ampleassume that a call isto be extended from the calling paystation T303 to the'called paysta-f tion T306, the; person at the calling paystaticn 'Ij303 initiates the call; whereby the line switch LS305 may select the trunk 320 extending-to the selector S300, whereupon the person at the calling.

paystation T303dials the; three digits comprising the directory number of the called paystation T7306. The selector 'S300,follows the first-digit selecting the group; of trunks, including the trunk 330, and then anidle trunk inthe sele ted group. For example,;t he;selector S300 may select the particular trunk;330 extending tcthe con nector 335. The connector-335 then responds to the second and ,third digits to select thetele phoneline 30] extending to the called paystation T306. The subsequent voperation of the connector 335 depend s upon the idle or busy condition of the called paystation T303 at this time 18 rent over 'the connection including the telephone line- 304. Also ,the connector 335 operates to reverse the polarity-of the loop circuit extending between the line relayin the connector 335 and the calling paystation T3 03; whereby the appaf ratll fi t the calling paystation T303 operates to; block the transmitter ofthe telephonelinstruf ment thereat in order to prevent-conversation. between ,theflpersonatthe vacallingpaystation T303 .and the person at the called paystation T306 The person at the calling paystation T303 may remove this blocked conditlonof the transmitter. of the telephonev instrument thereat by v depositing a coin at thecalling paystation T303; 1 whereby thetransmitter of the telephone instrument thereat is rendered operative so that; two-way conversation may take place between the calling paystation T303 and the called payer, station T306 The subsequent release of this} established connection is in accordance with c0n.-. ventional practice whereupon the coin'deposited atthecalling paystation T303 is collected; In; view of. the Ioregoing it is apparent that there has been provided in an automatictel'e phone system,v improved; switching repeater arrangement .for; selectively extending conned-f I tions from a, calling operator switchboard or from a calling"telephone station to a called opera ator switchboard; whereinthe repeateris seized overna common channel ,in either case and" 'wl ierein the repeater is selectively governed by the switching apparatus in accordance' with the origin of; thecall inorder selectivelyto control the reversal .o' f polarity over the common channel,

incidenttoranswering of the call at the called; operatorswitchboard.

While there has beenfdescribed what is' at present considered to be the preferred embodj ment or the linventiomit will be understoodthat various modifications may be made therein, and itis intended to cover in the appended claims all such modifications; as fall .withinthe true spirit n sc peio t i vent .Wh t is med s c -1.=In a telephone system, a first operator; posi-. tion,- atelephone 'station, a switch including a; pair xof line wipers and a test wiper and a control-wiper; a repeaterviincluding a supervisoryre lamav second roperatoltaposition, means controllable, from,-said first Operator position for ex-. tending a connection therefrom 'to; said switch; meansjcontrollable from said telephone station; for, extending a; connection; therefrom to. said; switchhmeans then controllable over either- 9f} said connections for operating said switch to testvia said test wipersaid repeater, means for.

causing said switch to seize saidrepeater in the event -it; is;te sted .as -;id le' means governed only, in the eventsaidifiqnnection is extended to said switch from gsaiditelephone stationfor establish-.1 ing a blocking control yia said controlwiper over; said, relay, ;-mea! 1 s thenion extending. a call from. said repeater; to said :second operator position meansresponsive: topnswering of said cell said second operator position for operating s ai d relay in the; event said blocking control is not established thereover', means' respons'iye to open ation;.gnsaidrelay f orreversing the polarity, of saidconnectionpyer. said line wipers, and means, responsive tmthe reversalof polarity of said con nection for returning an answer signalto saidfirst operatorposition. I v I .x f h 2. .In.a te1ephone system, a firstoperator pdsit' tipn; a telephone'f station, a switch including pair or line .wipers-,anda test wiper and a 0on from said telephone stationfor extending 'a con 7 nection therefrom to-said switch, means: then controllable overeither-of-said connectionsfor opera-ting said switch to test v'ia said test wiper" said repeater, means for causing saidswitch to seizesa-id repeater in the event it is tested as idle, means then for extending a callfrom said repeater to said second operator position, means responsive to answeringof-sai'd callat said-secand operator position for-energizing the winding-of said relay in the event said connectionis extended to said switch from said first operator position, means responsive to answering of said cell 'at said second operator position 'io'r shortcircuiting the winding of said'relayvia said confirst operator position.-

3. In a "telephone systernpa first opera-tor position, a telephone station; a switch including a pair of line wipers anda tjest wiper anda control wiper, a repeater including a-snpervisory-relay provided with a windingw-meansnormaliy connecting a firstpotentialwia 'a' resistor-to one terminal of the winding of 'saidrel'a'y, a second operator position; means "controllable from said first operator position for extending a connection therefrom to said switch, means controllable from said telephone station for extending 'a nonnection therefrom to said switch, means thencontrollable over either of said connections for operating said switch to test via said'tes't wiper said repeater, means for causing said switch to seize said repeater in the event i-tnis tested as idle, means governed only in the event said connection is extended to saidswitc' h irom said telephone station ior connecting a second notential via said controlwiper to said one terminal of thewindingofsaid relay, said secondfpote'ntial inthe event it is connected to .said one terminal of the winding ofsaid-relay overriding said firstpotential connected thereto via said resistor,

means then for extending -*a' ca1l said-repeater to said secondoperator-position, means responsive to answering-of said can at said second operator position 'for connectingsaid sec- 0nd potential to the other j-terminal of the winding of said relay, the w'inding'of said relay being energized in the'event said first and second potentials are respectively connected 'to s'a id one and other terminals thereof and being short-- circuited in the event said second potential is l connected'to both of said terminals thereof; saidrelay operating when the winding thereof en ergized, means responsive to operation of said relay for reversingthe polaritypf said com nection over said line wipers, and means re,- sponsive to the reversal of 'polarity'of saidconfirst operatorposition.

4. In a telephone system, 'afirstoperator posi tion, a 'telephonestation, a switch including a 1 nection for 1 returning an answer signal to said pair of line wipers and a test wiper and a control wiper and a device nonn'ally' connecting said 2d a control wiper to said test wiper,;s,:.repeater*in eluding a supervisory relay prov-ided wi-th a winding, means normally connecting a first potential via a resistor to one terminal of the winding of said relay, a second operator position meanscontrollable from said first operator position for extending a connection therefrom to :said switch, means controllable from said telephone station for extending a connection therefrom to said switch, means then controllable over either oil said connections for'operating said sw itchto 436st via said test wiper said 'repeaterand' for openating said device to disconnect saitl' con'trol wiper from said test wiper, means' for causing said switch to seize said repeater in the event is tested as idle, means governed only in the event said connection is extended to said from said telephone station for connecting a second potential via said device and said control wiper to said one terminal of the winding of said relay, said second potential in the event it in connected to said one terminal of the winding of said relay overriding said first potential connected thereto via said resistor, means then for extending a call from said-repeater to said second operator position,-me'ans responsive to answering of said call at said second operator position for connecting said second potential to the other terminal of the winding of said relay, the winding of said relay being energized in the event said first and second potentials are respectively connected to said one and other 'te'rminals thereof and being short-circuited in the event said second potential is connected to both of said terminals thereof, said relay operating when the winding thereof is energized, means trol wiper, a repeater including a trunk provided with a pair of line conductors and a test con doctor and a control conductor, said repeater also including a supervisory relay provided a winding, a second operator position, means controllable fromsaid first operator positionfor extending a connection therefrom'to said switch,

means controllable from said telephon'e station for extending a connection therefrom to said switch, means then controllable over either of said connections for-operating said switch to test via said test wiper said test conductor, means for causing said switchto seize said trunk in the event said test conductor is tested as idle,

means then for extending a call "from' said re peater to said second-operator position, means responsive to answeringof said' call at sa id se'c- 0nd operator position for energizing the winding of said relay in the event saidconnection is 'ex' from said telephone station, said relay operat ing when the winding thereof is energized, means responsive to operation of'sai-d relay for reversing the polarity of said 1 connection oversaid line conductors and said li'ne wipers, and

21 means responsive to the reversal of polarity of said connection for returning an answer signal to said first operator position.

CLARENCE E. LOMAX.

REFERENCES CITED The following references are of record in the file of this patent:

Number 22 UNITED STATES PATENTS Name Date Griffins Aug. 29, 1933 Martin Nov. 22, 1938 Evers Sept. 10, 1940 Lomax July 8, 1941 Goddard Jan. 23 1945 

